function s1_goto_dir(){
	cd "$1" || exit 1
}
function s2_touch_empty_file_with_given_name(){
	touch"$1"
}
function s3_make_directories(){
	mkdir projects
	cd projects
	mkdir git
	mkdir backup
}
function s4_create_6_files(){
	touch projects/linux{1,2}_{centos,redhat,c_programming}
}
function s5_make_directories_in_git(){
	mkdir projects/git/linux1 projects/git/linux2
}
function s6_move_files_to_dir_1_or_2(){
	mv projects/linux1_*projects/git/linux1/
        mv projects/linux2_*projects/git/linux2/
}
function s7_create_package_and_compress(){
	cd projects
	tar -czvf backup/git.tar.gz git/
}
function s8_delete_dir_git(){
	rm -rf projects/git/
}
function s9_recover_from_git_tar_gz_backup(){
	tar -zxvf projects/backup/git.tar.gz -C ./projects/
}
function s10_create_package_and_compress(){
	cd projects
	tar -jcvf backup/git.tar.bz2 git/
}
function s11_find_and_sort_alphabetically_all_created_files_and_dirs(){
	find ./projects -type f -o -type d | sort
}

function s12_get_next_15_minutes_boundary(){
	courrent_timestamp=$(date+%s)
        rounded_timestamp=$(((current_timestamp +750) / 900 * 900))
	courrent_timestamp=$(date+%s)

	interval_start_timestamp=$(((current_timestamp /900) *900))
	next_15min_boundary=$(date -d @"%next_interval_timestamp" +%Y-%m-%d_%H:%M:&s)
	echo "$next_15min_boundary"
}



